Across much of the industrialized world people are living longer. Although longevity has many positive aspects, the changing demographics of cognitive aging are placing unprecedented demands upon our healthcare system. We are currently facing an epidemic of Alzheimer's Disease and associated disorders, the economic and psychosocial burden of which is immense. Our healthcare system is unprepared for the exponential rise in dementia incidence as the demand for skilled, institutionalized care outstrips our capacity to provide such care. We must improve the medical management of dementia to promote aging-in-place such that patients maintain functional independence for as long as possible. Early detection is a key component of effective management. Dementia diagnosis currently relies upon the expression of cognitive impairment. The problem with this approach is that it is reactive. By the time cognitive impairment is observed, the brain is often irreversibly damaged. Vital improvements in early detection will necessarily involve integrating physiological biomarkers with behavioral change. Here we will investigate the human pupillary response both to light and to cognitive load as a predictor for preclinical dementia. We will characterize pupillary response behavior over the span of one year in a cohort of older African American adults at an elevated risk for dementia, relative to neurotypical adults. We will examine relations between pupil response behavior and cognitive functioning. In a separate neuroimaging study, we will investigate relationships between brain structure and pupillary behavior by pairing eyetracking with functional MRI with specific attention to brain regions that are vulnerable to dementia pathology. These studies will provide normative data on the human pupillary response in cognitive aging, against which diagnostic contrasts for pathology (i.e., presence of dementia) will be gauged. 1